This blogpost was originally published by the Huffington Post. It was co-authored by Bill Hemmings, Programme Manager for Aviation with Transport and Environmentand Vera Pardee, senior attorney with the Center for Biological Diversity's Climate Law Institute.

For airline passengers, it was a modest surcharge added to tickets in the name of fighting climate change: $3 for a transatlantic flight, for example. But for airlines, it has turned into a massive windfall. Delta collected as much as $40 million. United about the same. The amount reaped by the entire industry in 2012 has been estimated at up to $2 billion.

And none of the money went to its intended purpose -- a fact worth considering as the international community meets this week in Montreal to grapple with the vital question of how to reduce the aviation industry's massive greenhouse gas pollution.

Airlines levied the fees in anticipation of an expansion of the European Union's efforts to reduce carbon emissions. Europe's regional carbon-trading program started in 2005 and was expanded to cover European and international flights from the beginning of 2012.

But that expansion plan drew ferocious opposition, especially from U.S. airlines and their congressional allies, who spread wild claims that such modest fees would bankrupt the industry. They argued that aviation's carbon pollution should instead be addressed through international negotiations.

After relentless attacks, the EU suspended the measure for a year last November. That pleased the airlines -- but it didn't prompt them to return the carbon fees they'd already collected from passengers.

Allocating emissions from aircraft is exactly the task now facing negotiators in Montreal at a special meeting of the International Civil Aviation Organization (ICAO), the United Nations body tasked with the job of brokering a global deal to reduce aviation carbon emissions. Ironically, ICAO had ruled out a global measure in 2004, which prompted the EU to act.

It's important work. Aviation is one of the fastest-growing sources of carbon pollution, rising 3 to 4 percent per year. Getting a handle on this problem is critical if we're going to head off catastrophic climate change. Unfortunately, airlines have managed to help stymie international negotiations to curb emissions for 15 years.

The airlines' windfall carbon profits -- and what they show about the industry's propensity for hypocrisy and double-talk -- should be on ICAO negotiators' minds. After all, the industry and its spokesmen, such as Airlines For America (A4A), are hardly in need of additional funds to amplify their already extraordinary efforts to derail progress on reducing aviation's carbon pollution.

Instead, the money should go to developing countries that are desperate for the international community to commit substantial resources to fight climate change, particularly in areas vulnerable to extreme weather and sea-level rise. International sectors like aviation should contribute because of the global nature of airline travel.

The likelihood of ICAO agreeing on a global measure this year is fading even though international opposition to Europe's trading program -- including A4A's failed challenge at the European Court of Justice -- rested on the argument that it was ICAO's prerogative to solve these issues globally.

Instead, ICAO has already retreated to considering plan B, which is merely to develop rules for states or regions (such as the EU) to implement their own trading schemes pending an ICAO solution. But a plethora of complex, overlapping, and potentially competing regional programs is decidedly not the answer.

Moreover, regional-only plans harbor other Trojan horses. Most countries, including the U.S., report their aviation emissions to the UN on the basis of fuel sales as a proxy, and forecast trends based on whole flight emissions. That is, of course, the most sensible and direct way to measure airplane emissions. Yet Todd Stern, the U.S. representative at ICAO, seems to favour an alternative that counts emissions only over the sovereign airspace of countries.

For U.S. airlines, this plan would have the distinct advantage of reducing potential liability for aviation carbon by 75 percent. Singapore and the Gulf States, home to some of the world's largest aviation hubs, can presumably hardly keep a straight face: Given the miniscule time that air traffic to and from their airports travels across their sovereign airspace, their responsibility would end before the aircraft wheels were even up. Overall, the sovereign airspace approach would cover a mere 50 percent of global aviation emissions, since the high seas would be excluded.

U.S. positions on aviation carbon barely disguise A4A's agenda to avoid investment in fuel-efficient aircraft and other sensible approaches available today to reduce the warming effects caused by air travel. Transportation Secretary Ray LaHood has gone so far as to seek permanent exemption from Europe's aviation carbon trading program. But the U.S. aviation carbon footprint is some 25 percent of global levels , and America has an enormous responsibility to show constructive leadership.

Washington should reject the self-interested arguments peddled by lobbyists now flush with money from unwitting passengers who thought they were helping fight climate change. The Obama administration should now act upon the hard facts underlining the need to curb U.S. aviation emissions. It's time to turn climate-change rhetoric into constructive action.